Method and apparatus for the manufacture of insulating bodies



April 4, 1950 K. F. GREENE 2,503,041 m1-Hon ma APPARATUS Fon 'mEumm-ACME oF-INsULATING Booms y lea oct. 1o; 1947 ATTORNEY:

Patented lApr. 4, 1950 METHOD AND APPARATUS FOR THE MANU- FACTURE OF INSULATING BODIES Kenneth F. Greene, Griggstown, N. J., assignor toJohns-Manville Corporation, New' York, N. Y., a corporation of New YorkApplication October 10, 1947, Serial No. 779,048

6 Claims. (Cl. 154-27) The instant invention relates to improved methodsand apparatus for the production of fibrous insulating bodies and thelike and is particularly concerned with improvements in the known methodof forming insulating coverings by rolling a lap or layer of relativelyloose, bulky, compressible, brous material, such for example as asbestosfiber, on a mandrel, the layer carrying a suitable binder. Suchcoverings may be employed either in tubular form for pipe and tankcoverings and the like, or may be slit longitudinally before the binderis set and straightened out into blanket form.

In the known methods a layer of the brous material is delivered by aroll or apron into position to be Wound up on a mandrel. The mandrel issupported on a retractable carriage, the carriage being moved away fromthe delivery device solely by the force exerted by the body of materialas it is built up on the mandrel. The density of the body hence will bedetermined by the density and compressibility of the particular materialbeing used and the resistance to movement exerted by the carriage at anyparticular time, no positive control being obtainable. Under thesecircumstances it has been impossible from a practical standpoint toobtain low density products. It will be readily appreciated that if themandrel carriage is of such construction that it may easily be forcedaway from the delivery device, wide variation in the density of thecovering will result as minor factors will exert disproportionateiniiuence on the movement of the carriage. On the other hand, if thecarriage is loaded suiilciently or its resistance to movement isotherwise increased to substantially eliminate the influence of suchminor factors, the density of the body will necessarily be high. Also,it has been found substantially impossible to secure uniformity betweensuccessive covering sections, even at the densities ordinarily desiredfor insulation, ldue to the lack of control of the systern.

A principal object of the instant invention is the provision of a methodand apparatus by which positive control of the density of the coveringmay be maintained. More particularly it is an object of the invention toprovide a method and apparatus in which the withdrawal movement of themandrel is mechanically controlled.

A further object of the invention is the provision of such method andapparatus in which the mandrel is carried by 'a movable carriage and.mechanism is employed to withdraw the carriage at a predetermined ratewhich may be either constant or variable, depending upon the particulartype of product desired. The instant invention thus eliminates thedisadvantages of the known systems and permits coverings to be madewhich are of a controlled density, successive coverings made by themachine under the same conditions having substantially 'the sameproperties.

My invention will be more fully understood and further objects andadvantages thereof will become apparent when reference is made to themore detailed description of a preferred embodiment of the inventionwhich is to follow and to the accompanying drawings in which:

Fig. 1 is a diagrammatic, side elevational View of an apparatus inaccordance with the instant invention and for carrying out the methodthereof Fig. 2 is a top plan view of the apparatus of Fig. 1;

Fig. 3 is a side elevational view, on an enlarged scale, of aportion ofthe apparatus illustrating one stage'in the operation;

Fig. 4 is a view similar to Fig. `3 illustrating a later stage in theoperation; and,

Fig. 5 is a perspective view of a pipe covering as made by the instantinvention.

Referring now to the ldrawings and particularly to Figs. 1-4 inclusive,the apparatus shown comprises a device indicated generally at I0 forforming a lap or layer of insulating material,

such as asbestos ber or other loose, brous material, and conveying itinto position to be picked up by a mandrel l2. In the apparatusspecifically illustrated, device l0 includes an apron I4 supported onspaced rolls I6 and I8, at least one of the rolls being driven to causethe upper reach of the apron to move in the direction indicated by thearrow (see Fig. 1). The drive, which may take any suitable form, is notillustrated. Supported above the apron and extending substantially thewidth of the apron is a fiber supplying device 2liv suitably in the formof a cabinet or box and having a mouth or opening 22 above the surfaceof the apron. The cabinet deposits opened, dispersed ber onto the apronin controlled quantities to provide a substantially uniform thicknessand density layer. Also, supported above the apron and in position todischarge a binder onto the layer of fibers is a binder applying device24. As will be appreciated, this device may vary depending upon theparticular type of binder to be used but preferably consists of a nozzlemember extending the width of the layer on the apron and having aplurality of spray openings. The nozzle may be connected to any suitablesource of binder supply (not shown). It will be understood that theconstruction of device I described above is for purposes of illustrationonly and that any suitable or conventional apparatus may be used toprovide a fibrous, binder-containing layer of substantially uniformdensity in position to be picked up by mandrel I2. The particularfibrous material may be any bulky, readily compressible material whichis adapted to be used with equipment of the above type for theproduction of insulating tubes, blankets, and the like. Asbestos fibersare a preferred example. Also, substantial proportions, say up to 50% ormore by weight of a powdered or fibrous filler, may be employe with theasbestos bers if desired. i

In accordance with the instant invention mandrel I2 is mounted for freerotation in bearings 26 supported on a carriage 28. Carriage 28 ismovable toward and away from roll I8 and preferably for this purposeincludes wheels or rollers 3D mounted to ride on tracks 32 forming theupper rails of a table 34.

The device for mechanically retracting the carriage is indicatedgenerally at 36, the device in the embodiment vshown comprising frontand rear bearings 38 and 4I), respectively, and a rotatable butlongitudinally xed rod or shaft 42 mounted in the bearings. Shaft 42includes a threaded section 44 received in a nut 46 carried by a framemember 48 of carriage 28 and in xed relationship thereto. Shaft 42 isadapted to be positively driven in a direction to cause rearwardmovement of the carriage by any suitable means, such as motor 50,operatively connected to the shaft through speed control device 52 ofany suitable type and belt drive, or the like 54.

In the operation of the apparatus described above and in carrying outthe method of the instant invention, carriage 28 is first movedforwardly to bring the mandrel in contact'with the apron on roll I8.This may be effected through the medium of motor 50 and the driveconnection or, alternatively, nut 46 may be of a conventional type whichpermits release of its threaded relationship to the shaft, in whichevent the carriage may be quickly moved to bring the mandrel intostarting position by manual or mechanical operation, as desired. Device20 is operated to deliver a layer of fibrous material, with or without afiller, as desired, and carrying a binder applied by spray device 24, tothe bight between the apron and the mandrel, the mandrel rotatingthrough its contact with the apron. After the layer reaches the bightand the rst layer is wound thereon, the drive mechanism is operated tocause gradual retraction of carriage 28 and, hence, of mandrel I2 as thebody builds up on the mandrel. The rate of retraction of the carriageand, hence, of the mandrel from the vicinity of end roll I8 of the apronconveyor, is adjusted to the value required, the latter depending uponthe thickness, bulkiness and compressibility of the layer of material tobe delivered by the apron and the desired density of the finishedproduct. Due to the light, uffy, open condition of the brous materialissuing from box 2U, the layer on the apron is relatively thick andbulky, the layer becoming compressed as it is applied to the mandrel butthe degree of compression is under the positive control of theretraction means. If a light density product is desired the mandrelisrelatively rapidly withdrawn. On the other hand, the rate ofretraction of the mandrel relatively to the deposit of the brousmaterial may be reduced to produce substantial compression of thematerial and hence a product of greater density. Thus, where the layeris supplied at a given thickness and density, the control of mandrelmovement provides control of density of the product.

When a sufficient number of convolutions has been built up on themandrel to produce a covering of the selected thickness and density, thewithdrawal movement of the mandrel is stopped and the mandrel lifted outto permit the tubular product to be stripped from it. Where the productis to be used for a pipe covering orthe like in tubular form, the binderis dried or cured and the tube then divided longitudinally ondiametrically opposite lines to produce semi-cylindrical pipe coveringsections 54 and 56, as illustrated in Fig. 5. If a blanket type productis desired the tubular covering is longitudinally slit before the bindercan take a permanent set and the tube is flattened out. The binder isthen dried or cured.

After removal of the covering from the mandrel the carriage ismoved-forwardly to again bring it into contact with the apron at roll I8and the operation is repeated. Forward movement of the carriage may becaused by reversing the drive, or nut 46 may be of such constructionthat it can be released from shaft 44 to permit the carriage to bemanually or otherwise quickly moved to bring the mandrel into operatingposition, as previously pointed out.

The method and apparatus described above provide accurate control of theproperties of the product and insure that a succession of products canbe made having substantially identical properties. The coverings can bemade within a wide range of densities and may be of non-uniformdensities if desired. For example, a product of gradually decreaseddensity outwardly from the center may be obtained by withdrawal movementof the mandrel at a constant rate. On the other hand, if the density ofthe covering is to be uniform throughout its thickness, the rate ofwithdrawal of the mandrel will be gradually decreased. Also, a productmay be made with higher densities at the inner and outer faces with aninterior section of lower density by rst withdrawing the carriage at arelatively slow rate, then at a higher rate and iinally again at aslower rate.

Having thus described my invention in rather full detail, it will beunderstood that these details need not be strictly adhered to but thatvarious changes and modifications may suggest themselves to one skilledin the art, all falling within the scope of the invention as defined bythe subjoined claims What I claim is:

1. In a method of producing an insulating body including delivering alayer of compressible material between a surface and a rotatablemandrel, the improvement comprising, winding the layer on the mandreland simultaneously moving the mandrel away from the surface underpositive control at a uniform predetermined rate.

2. In a method of producing an insulating body including delivering alayer of compressible lnsulating material between a moving surface and arotatable mandrel, the improvement comprising, supporting the mandrelfor movement away from the surface, winding the layer on the mandrel andsimultaneously moving said mandrel imderpositive control to withdraw'said mandrel from said surface at a uniform predetermined rate duringthe winding operation.

3. In an apparatus for producing an insulating body including means fordelivering a layer oi insulating material to a surface and a mandrel forpicking up the layer from saidsuriace. the improvement comprising, amovabie mounting for supporting the mandrel for Ires rotation, anddriven means for moving said mounting at a predetermined rate away fromsaid surface.

4. In an apparatus for producing an insulating body including means fordelivering a layer of insulating material to a surface and a mandrel forpicking up the layer from said suriace, the improvement comprising, amovable mounting supporting lthe mandrel for -free rotation, and meansfor moving said mounting laway from said .surface at a predeterminedrate, said last named means including a positive drive mechanism.

5. In an apparatus for producing an insulating 'body including means fordelivering a layer of insulating material to a surface and a mandrel forpicking up the layer from said surface, the

improvement comprising, a carriage.. bearings on 25 2,019,417

said carriage tor supporting said mandrel in l iixed relative positionthereto and for n'ee rotation. and means for retracting said carriage ata predetermined rate.

6. In an apparatus for producing an insulating body including means `fordelivering a layer or insulating material to a surface and a mandrel forpicking up the layer from said surface, the improvement comprising, acarriage, a frame supporting the carriage for travel thereon, bearingson said carriage for supporting said mandrel in ilxed relative positionthereto and for :tree rotation, a nut iixed to said carriage, a shaftrotatably supported on the frame and threaded into said nut, and meansfor rotating the shaft.

KENNETH F. GREENE.

REFERENCES CITED The following references are of record in the me ofthis patent:

UNITED STATES PATENTS Number Name Date 1,316,119 Sullivan Sept. 16, 19191,844,647 Everett Feb. 9, 1932 4 vKing Oct. v29, 1935 2,353,821

Fourness et al July 18, 1944

